SOLUTION: Jill is 3 times as old as her cousin Dennis. In 4 years, she will be twice as old as Dennis. What will the sum of their ages be in 4 years?

Question 835961: Jill is 3 times as old as her cousin Dennis. In 4 years, she will be twice as old as Dennis. What will the sum of their ages be in 4 years?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Jill is 3 times as old as her cousin Dennis. In 4 years, she will be twice as old as Dennis.
Equations:
j = 3d
j+4 = 2(d+4)
------
Substitute for "j" and solve for "d"::
3d+4 = 2d+8
d = 4 (Dennis's age now)
---
j = 3d = 12 years (Jill's age now)
------------------------------------------
What will the sum of their ages be in 4 years?
Ans: (4+4)+(12+4) = 24
===========================
Cheers,
Stan H.

RELATED QUESTIONS
Carl and dennis are brothers. The sum of their age is 29. In 6 year time Carl will be the (answered by ankor@dixie-net.com)

Mary is three times as old as Jill. In five years, she will be twice as old as Jill. Find (answered by Alan3354,ikleyn)

Carl and Dennis are brothers. The sum of their age is 29. In 6 years time Carl will be... (answered by mananth)

1. The sum of the ages of John and Jacob is 20 years. Two years from now , one will be... (answered by ankor@dixie-net.com)

Ann is 3 times as old as cousin Bob. Four years from now she will be one year more than... (answered by stanbon)

Claire's cousin is now 3 times as old as Claire. In 10 years, her cousin will be twice as (answered by Alan3354,ikleyn)

Sofia is 7 years older than her cousin. In 4 years, she will be twice as old as her... (answered by macston)

Sofia is 5 times as old as her cousin. Four years from now she will be 3 times as old as... (answered by Deina)

Ann is 3 times as old as her daughter. In 3 years time, she will be twice the age of the... (answered by Lola77479)